Greatly variable magnification zoom lens system of large aperture ratio

Abstract

Attention has been directed to the fact that in zoom objective lens systems, the compensator for compensating the focal point shift caused by the zoom movement of the variator has generally two solution curves. A novel zooming mechanism such that the compensator is transferred from one to the other solution curve in the middle position of the zooming is employed in a zoom lens system to which this invention relates. As a result, this permits the variator and compensator to partake equally the function on magnification variation to enable minimizing the image shift sensitivity of each movable lens group and making the diameter of the front lens element small, and moreover compensating the variation of aberrations to very good degree.

What is claimed is: 
     
       1. A greatly variable magnification zoom lens of large aperture ratio comprising lens group I of positive power, lens group II of negative power, lens group III of positive power and lens group IV arranged successively on the common optical axis whereby lens groups II and III are movable relative to lens group I to effect a continuous variation of magnification, said zoom lens system satisfying the conditions that the equivalent focal lengths and magnification powers of the lens groups, designated as fi, mi (i = 1 - 4) respectively, are defined by   0.24f.sub.i > f.sub.2  < 0.25f.sub.1       0.57f.sub.1 < f.sub.3 < 0.59f.sub.1     and when the equivalent focal length of the entire optical system varies from the minimum to the maximum with continuous variation in magnification, m 2  and m 1  not only increase in simple fashion, but coincide with each other at unity magnification (or m 2  = m 1  = -1) within the zooming region, whereby the relationship between the distance through which lens group II is displaced from the minimum equivalent focal length position to the coincidence position and the total distance through which lens group II is displaced from the minimum to maximum equivalent focal length position, designated as V m2  = 1 and V max  respectively, is established that in the ratio of V m2  = 1 /V max , designated as α     α= 0.8     2.   
     
     
       2. A zoom lens system comprising lens group I of positive power, lens group II of negative power, lens group III of positive power and lens group IV arranged successively on the common optical axis whereby lens groups II and III are movable relative to lens group I to effect a continuous variation of magnification, said zoom lens system having the following constitutional data:   f = 7.238 - 68.79 F/1.4                                                   
Zoom Ratio: 9.504                                                         
Image Angle: 54.2° - 5.8°                                   
ri          di         ni          vi                                     
______________________________________                                    
191.7       1.7        1.80518     25.4                                   
58.365      0.366                                                         
62.232      8.5        1.64000     60.2                                   
-168.79     0.2                                                           
43.4021     6.5        1.64000     60.2                                   
207.42      (d.sub.6)                                                     
267.23      1.0        1.71300     54.0                                   
18.235      5.3                                                           
-29.654     0.7        1.69680     55.7                                   
18.9525     4.5        1.80518     25.4                                   
125.35      (d.sub.11)                                                    
5852.3      1.19       1.80518     25.4                                   
43.22       6.98       1.6400      60.2                                   
-37.9       0.2                                                           
38.2234     3.71       1.65160     58.6                                   
224.952     (d.sub.16)                                                    
-60.061     0.7        1.65160     58.6                                   
21.63       2.3        1.80518     25.4                                   
50.002      2.35                                                          
0.          11.0       1.63854     55.4                                   
0.          6.06                                                          
21.63       3.37       1.76200     40.2                                   
63.98       2.62                                                          
12.0776     3.07       1.71300     54.0                                   
29.918      1.83       2.80518     25.4                                   
8.5258      6.07                                                          
-13.987     1.0        1.80518     25.4                                   
57.565      3.96       1.67790     55.3                                   
-19.74      0.41                                                          
117.089     2.03       1.66446     35.8                                   
-32.11      0.1                                                           
21.7328     2.13       1.58144 40.7                                       
-132.36     1.2                                                           
0.          6.8        1.63854     55.4                                   
0.                                                                        
        f = 7.238   f = 15.72   f = 68.79                                 
d.sub.6 1.000       14.826      28.652                                    
d.sub.11                                                                  
        68.654      47.639      12.561                                    
d.sub.16                                                                  
        2.006       9.195       30.446                                    
______________________________________                                    
 f.sub.1 = 61.153                                                         
 f.sub.2 = -15.120                                                        
 f.sub.3 = 35.716                                                         
 α = 0.8.                                                           
     
     
     
       3. A zoom lens system comprising lens group I of positive power, lens group II of negative power, lens group III of positive power and lens group IV arranged successively on the common optical axis whereby lens groups II and III are movable relative to lens group I to effect a continuous variation of magnification, said zoom lens system having the following constitutional data:f = 7.239 - 68.83 F/1.4Zoom Ratio: 9.508Image Angle: 54.2° - 5.8°ri          di         ni          vi______________________________________113.17      1.7        1.80518     25.449.111      8.7        1.64000     60.2-314.35     0.246.653      6.0        1.64000     60.2184.659     (d 5 )226.12      1.0        1.71300     54.018.956      5.2-32.642     0.7        1.69680     55.718.272      3.5        1.80518     25.476.2925     (d 10 )-155.74     2.56       1.80518     25.458.649      0.2867.677      7.78       1.64000     60.2-33.25      0.235.292      4.17       1.65160     58.6264.487     (d 16 )-58.196     0.7        1.65160     58.620.822      2.3        1.80518     25.451.8332     2.350.          11.0       1.63854     55.40.          5.522.253      3.73       1.74400     44.859.119      1.911.689      3.71       1.71300     54.033.562      1.84       1.80518     25.48.2621      5.41-13.651     0.99       1.78470     26.250.924      3.67       1.67790     53.3-18.928     0.19118.55      1.84       1.66446     35.8-32.295     0.0820.755      2.08       1.58921     41.1-276.285    1.260.          6.8        1.63854     55.40.        f = 7.239   f = 15.72   f = 68.83d 5  1.135       14.961      28.787d 10         66.848      45.835      10.742d 16         2.033       9.220       30.487______________________________________ f 1  = 62.640 f 2  = -15.119 f 3  = 35.714 α = 0.8. 
     
     
       4. A zoom lens system comprising lens group I of positive power, lens group II of negative power, lens group III of positive power and lens group IV arranged successively on the common optical axis whereby lens groups II and III are movable relative to lens group I to effect a continuous variation of magnification, said zoom lens system having the following constitutional data:f = 7.239 - 68.83 F/1.4Zoom Ratio: 9.508Image Angle: 54.2° - 5.8°ri          di         ni          vi______________________________________168.29      1.7        1.80518     25.454.169      0.7855.638      9.0        1.64000     60.2-169.83     0.243.387      6.0        1.64000     60.2164.541     (d 6 )414.98      1.0        1.71300     54.018.635      5.2-31.727     0.7        1.69680     55.719.199      3.5        1.80518     25.4102.561     (d 11 )200.58      1.5        1.80518     25.442.381      0.9949.967      6.5        1.64000     60.2-38.752     0.236.555      3.0        1.65160     58.6108.907     (d 17 )-73.881     0.7        1.65160     58.622.26       2.3        1.80518     25.4-81.113     0.7        1.65160     58.622.079      2.3        1.80518     25.442.8213     2.350.          11.0       1.63854     55.40.          5.521.7        3.15       1.75700     47.965.65       0.111.5        3.88       1.71300     54.036.0        1.59       1.80518     25.48.13        6.29-13.8       1.72       1.78470     26.249.46       3.9        1.67790     53.3-18.66      1.76137.39      2.36       1.66446     35.8-31.92      0.121.42       1.8        1.59270     35.61049.52     1.20.          6.8        1.63854     55.40.        f = 7.239   f = 15.72   f = 68.83d 8  1.339       15.165      28.991d 13         69.980      48.967      13.874d 19         2.056       9.243       30.510______________________________________ f 1  = 61.140 f 2  = 15.119 f 3  = 35.714 α = 0.8. 
     
     
       5. A zoom lens system comprising lens group I of positive power, lens group II of negative power, lens group III of positive power and lens group IV arranged successively on the common optical axis whereby lens group II and III are movable relative to lens group I to effect a continuous variation of magnification, said zoom lens system having the following constitutional data:f = 7.239 - 68.83 F/1.4Zoom Ratio: 9.508Image Angle: 54.2° - 5.8°ri          di          ni         vi______________________________________-452.18     1.7        1.80518     25.491.642      1.1395.327      6.5        1.71300     54.0-169.32     0.2182.65      4.0        1.60311     60.7-23035      0.240.571      5.2        1.60311     6.0793.8515     (d 8 )101.06      0.7        1.71300     54.020.514      5.5-31.549     0.7        1.69680     55.718.838      3.5        1.80518     25.450.9964     (d 13 )130.16      1.0        1.80518     25.448.981      1.3457.122      6.0        1.64000     60.2-40.845     0.238.987      2.5        1.65160     58.6109.837     (d 19 )44.8785     2.350.          11.0       1.63854     55.40.          6.021.144      2.45       1.76200     40.271.845      1.411.782      3.62       1.71300     54.032.121      1.42       1.80518     25.48.3216      6.18-13.972     1.0        1.78470     26.253.881      4.66       1.67790     53.3-18.843     0.5133.88      1.84       1.66446     35.8-31.226     0.122.425      1.89       1.58900     48.6315.807     1.20.          6.8        1.63854     55.40.        f = 7.239   f = 15.72   f = 68.83d 6  1.179       15.005      28.831d 11         68.564      47.551      12.458d 17         2.121       9.308       30.575______________________________________ f 1  = 61.140 f 2  = -15.119 f 3  = 35.714 α = 0.8.